2 * kernel userspace event delivery
4 * Copyright (C) 2004 Red Hat, Inc. All rights reserved.
5 * Copyright (C) 2004 Novell, Inc. All rights reserved.
6 * Copyright (C) 2004 IBM, Inc. All rights reserved.
8 * Licensed under the GNU GPL v2.
11 * Robert Love <rml@novell.com>
12 * Kay Sievers <kay.sievers@vrfy.org>
13 * Arjan van de Ven <arjanv@redhat.com>
14 * Greg Kroah-Hartman <greg@kroah.com>
17 #include <linux/spinlock.h>
18 #include <linux/string.h>
19 #include <linux/kobject.h>
20 #include <linux/export.h>
21 #include <linux/kmod.h>
22 #include <linux/slab.h>
23 #include <linux/user_namespace.h>
24 #include <linux/socket.h>
25 #include <linux/skbuff.h>
26 #include <linux/netlink.h>
28 #include <net/net_namespace.h>
32 char uevent_helper[UEVENT_HELPER_PATH_LEN] = CONFIG_UEVENT_HELPER_PATH;
35 struct list_head list;
38 static LIST_HEAD(uevent_sock_list);
41 /* This lock protects uevent_seqnum and uevent_sock_list */
42 static DEFINE_MUTEX(uevent_sock_mutex);
44 /* the strings here must match the enum in include/linux/kobject.h */
45 static const char *kobject_actions[] = {
47 [KOBJ_REMOVE] = "remove",
48 [KOBJ_CHANGE] = "change",
50 [KOBJ_ONLINE] = "online",
51 [KOBJ_OFFLINE] = "offline",
55 * kobject_action_type - translate action string to numeric type
57 * @buf: buffer containing the action string, newline is ignored
58 * @len: length of buffer
59 * @type: pointer to the location to store the action type
61 * Returns 0 if the action string was recognized.
63 int kobject_action_type(const char *buf, size_t count,
64 enum kobject_action *type)
66 enum kobject_action action;
69 if (count && (buf[count-1] == '\n' || buf[count-1] == '\0'))
75 for (action = 0; action < ARRAY_SIZE(kobject_actions); action++) {
76 if (strncmp(kobject_actions[action], buf, count) != 0)
78 if (kobject_actions[action][count] != '\0')
89 static int kobj_bcast_filter(struct sock *dsk, struct sk_buff *skb, void *data)
91 struct kobject *kobj = data, *ksobj;
92 const struct kobj_ns_type_operations *ops;
94 ops = kobj_ns_ops(kobj);
95 if (!ops && kobj->kset) {
96 ksobj = &kobj->kset->kobj;
97 if (ksobj->parent != NULL)
98 ops = kobj_ns_ops(ksobj->parent);
101 if (ops && ops->netlink_ns && kobj->ktype->namespace) {
102 const void *sock_ns, *ns;
103 ns = kobj->ktype->namespace(kobj);
104 sock_ns = ops->netlink_ns(dsk);
105 return sock_ns != ns;
112 static int kobj_usermode_filter(struct kobject *kobj)
114 const struct kobj_ns_type_operations *ops;
116 ops = kobj_ns_ops(kobj);
118 const void *init_ns, *ns;
119 ns = kobj->ktype->namespace(kobj);
120 init_ns = ops->initial_ns();
121 return ns != init_ns;
127 static int init_uevent_argv(struct kobj_uevent_env *env, const char *subsystem)
131 len = strlcpy(&env->buf[env->buflen], subsystem,
132 sizeof(env->buf) - env->buflen);
133 if (len >= (sizeof(env->buf) - env->buflen)) {
134 WARN(1, KERN_ERR "init_uevent_argv: buffer size too small\n");
138 env->argv[0] = uevent_helper;
139 env->argv[1] = &env->buf[env->buflen];
142 env->buflen += len + 1;
146 static void cleanup_uevent_env(struct subprocess_info *info)
152 * kobject_uevent_env - send an uevent with environmental data
154 * @action: action that is happening
155 * @kobj: struct kobject that the action is happening to
156 * @envp_ext: pointer to environmental data
158 * Returns 0 if kobject_uevent_env() is completed with success or the
159 * corresponding error when it fails.
161 int kobject_uevent_env(struct kobject *kobj, enum kobject_action action,
164 struct kobj_uevent_env *env;
165 const char *action_string = kobject_actions[action];
166 const char *devpath = NULL;
167 const char *subsystem;
168 struct kobject *top_kobj;
170 const struct kset_uevent_ops *uevent_ops;
174 struct uevent_sock *ue_sk;
177 pr_debug("kobject: '%s' (%p): %s\n",
178 kobject_name(kobj), kobj, __func__);
180 /* search the kset we belong to */
182 while (!top_kobj->kset && top_kobj->parent)
183 top_kobj = top_kobj->parent;
185 if (!top_kobj->kset) {
186 pr_debug("kobject: '%s' (%p): %s: attempted to send uevent "
187 "without kset!\n", kobject_name(kobj), kobj,
192 kset = top_kobj->kset;
193 uevent_ops = kset->uevent_ops;
195 /* skip the event, if uevent_suppress is set*/
196 if (kobj->uevent_suppress) {
197 pr_debug("kobject: '%s' (%p): %s: uevent_suppress "
198 "caused the event to drop!\n",
199 kobject_name(kobj), kobj, __func__);
202 /* skip the event, if the filter returns zero. */
203 if (uevent_ops && uevent_ops->filter)
204 if (!uevent_ops->filter(kset, kobj)) {
205 pr_debug("kobject: '%s' (%p): %s: filter function "
206 "caused the event to drop!\n",
207 kobject_name(kobj), kobj, __func__);
211 /* originating subsystem */
212 if (uevent_ops && uevent_ops->name)
213 subsystem = uevent_ops->name(kset, kobj);
215 subsystem = kobject_name(&kset->kobj);
217 pr_debug("kobject: '%s' (%p): %s: unset subsystem caused the "
218 "event to drop!\n", kobject_name(kobj), kobj,
223 /* environment buffer */
224 env = kzalloc(sizeof(struct kobj_uevent_env), GFP_KERNEL);
228 /* complete object path */
229 devpath = kobject_get_path(kobj, GFP_KERNEL);
236 retval = add_uevent_var(env, "ACTION=%s", action_string);
239 retval = add_uevent_var(env, "DEVPATH=%s", devpath);
242 retval = add_uevent_var(env, "SUBSYSTEM=%s", subsystem);
246 /* keys passed in from the caller */
248 for (i = 0; envp_ext[i]; i++) {
249 retval = add_uevent_var(env, "%s", envp_ext[i]);
255 /* let the kset specific function add its stuff */
256 if (uevent_ops && uevent_ops->uevent) {
257 retval = uevent_ops->uevent(kset, kobj, env);
259 pr_debug("kobject: '%s' (%p): %s: uevent() returned "
260 "%d\n", kobject_name(kobj), kobj,
267 * Mark "add" and "remove" events in the object to ensure proper
268 * events to userspace during automatic cleanup. If the object did
269 * send an "add" event, "remove" will automatically generated by
270 * the core, if not already done by the caller.
272 if (action == KOBJ_ADD)
273 kobj->state_add_uevent_sent = 1;
274 else if (action == KOBJ_REMOVE)
275 kobj->state_remove_uevent_sent = 1;
277 mutex_lock(&uevent_sock_mutex);
278 /* we will send an event, so request a new sequence number */
279 retval = add_uevent_var(env, "SEQNUM=%llu", (unsigned long long)++uevent_seqnum);
281 mutex_unlock(&uevent_sock_mutex);
285 #if defined(CONFIG_NET)
286 /* send netlink message */
287 list_for_each_entry(ue_sk, &uevent_sock_list, list) {
288 struct sock *uevent_sock = ue_sk->sk;
292 if (!netlink_has_listeners(uevent_sock, 1))
295 /* allocate message with the maximum possible size */
296 len = strlen(action_string) + strlen(devpath) + 2;
297 skb = alloc_skb(len + env->buflen, GFP_KERNEL);
302 scratch = skb_put(skb, len);
303 sprintf(scratch, "%s@%s", action_string, devpath);
305 /* copy keys to our continuous event payload buffer */
306 for (i = 0; i < env->envp_idx; i++) {
307 len = strlen(env->envp[i]) + 1;
308 scratch = skb_put(skb, len);
309 strcpy(scratch, env->envp[i]);
312 NETLINK_CB(skb).dst_group = 1;
313 retval = netlink_broadcast_filtered(uevent_sock, skb,
317 /* ENOBUFS should be handled in userspace */
318 if (retval == -ENOBUFS || retval == -ESRCH)
324 mutex_unlock(&uevent_sock_mutex);
326 /* call uevent_helper, usually only enabled during early boot */
327 if (uevent_helper[0] && !kobj_usermode_filter(kobj)) {
328 struct subprocess_info *info;
330 retval = add_uevent_var(env, "HOME=/");
333 retval = add_uevent_var(env,
334 "PATH=/sbin:/bin:/usr/sbin:/usr/bin");
337 retval = init_uevent_argv(env, subsystem);
342 info = call_usermodehelper_setup(env->argv[0], env->argv,
343 env->envp, GFP_KERNEL,
344 NULL, cleanup_uevent_env, env);
346 retval = call_usermodehelper_exec(info, UMH_NO_WAIT);
347 env = NULL; /* freed by cleanup_uevent_env */
356 EXPORT_SYMBOL_GPL(kobject_uevent_env);
359 * kobject_uevent - notify userspace by sending an uevent
361 * @action: action that is happening
362 * @kobj: struct kobject that the action is happening to
364 * Returns 0 if kobject_uevent() is completed with success or the
365 * corresponding error when it fails.
367 int kobject_uevent(struct kobject *kobj, enum kobject_action action)
369 return kobject_uevent_env(kobj, action, NULL);
371 EXPORT_SYMBOL_GPL(kobject_uevent);
374 * add_uevent_var - add key value string to the environment buffer
375 * @env: environment buffer structure
376 * @format: printf format for the key=value pair
378 * Returns 0 if environment variable was added successfully or -ENOMEM
379 * if no space was available.
381 int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...)
386 if (env->envp_idx >= ARRAY_SIZE(env->envp)) {
387 WARN(1, KERN_ERR "add_uevent_var: too many keys\n");
391 va_start(args, format);
392 len = vsnprintf(&env->buf[env->buflen],
393 sizeof(env->buf) - env->buflen,
397 if (len >= (sizeof(env->buf) - env->buflen)) {
398 WARN(1, KERN_ERR "add_uevent_var: buffer size too small\n");
402 env->envp[env->envp_idx++] = &env->buf[env->buflen];
403 env->buflen += len + 1;
406 EXPORT_SYMBOL_GPL(add_uevent_var);
408 #if defined(CONFIG_NET)
409 static int uevent_net_init(struct net *net)
411 struct uevent_sock *ue_sk;
412 struct netlink_kernel_cfg cfg = {
414 .flags = NL_CFG_F_NONROOT_RECV,
417 ue_sk = kzalloc(sizeof(*ue_sk), GFP_KERNEL);
421 ue_sk->sk = netlink_kernel_create(net, NETLINK_KOBJECT_UEVENT, &cfg);
424 "kobject_uevent: unable to create netlink socket!\n");
428 mutex_lock(&uevent_sock_mutex);
429 list_add_tail(&ue_sk->list, &uevent_sock_list);
430 mutex_unlock(&uevent_sock_mutex);
434 static void uevent_net_exit(struct net *net)
436 struct uevent_sock *ue_sk;
438 mutex_lock(&uevent_sock_mutex);
439 list_for_each_entry(ue_sk, &uevent_sock_list, list) {
440 if (sock_net(ue_sk->sk) == net)
443 mutex_unlock(&uevent_sock_mutex);
447 list_del(&ue_sk->list);
448 mutex_unlock(&uevent_sock_mutex);
450 netlink_kernel_release(ue_sk->sk);
454 static struct pernet_operations uevent_net_ops = {
455 .init = uevent_net_init,
456 .exit = uevent_net_exit,
459 static int __init kobject_uevent_init(void)
461 return register_pernet_subsys(&uevent_net_ops);
465 postcore_initcall(kobject_uevent_init);